Writing Text

Text Writing API. More...

Functions list
void	gl_draw_char (char ch, gl_coord_t x, gl_coord_t y)
	Write a single character on a display. More...
void	gl_draw_text (const char *__generic text, gl_coord_t x, gl_coord_t y)
	Write a text on display. More...
gl_size_t	gl_get_text_dimensions (const char *__generic text)
	Calculate text dimension. More...

Detailed Description

This API is used for writing and managing text on the display. Desired font must be generated by the resource manager from NECTO Studio.

Function Documentation

gl_draw_char()

void gl_draw_char	(	char	ch,
		gl_coord_t	x,
		gl_coord_t	y
	)

This function writes a single character on a display with top left pixel situated at given x and y coordinates. Character look depends on currently active font, pen, and orientation. Background color can also be specified. It is possible to rotate character using the gl_set_font_orientation. If the given character is written out of the display, the surplus will be cropped. Character that can be drawn is determined by the used font; if not supported by the font, it won't be printed and the behavior in that case is undefined. Character '\n' is not suported.

Parameters

[in]	ch	Character to write.
[in]	x	X coordinate. See gl_coord_t definition for detailed explanation.
[in]	y	Y coordinate. See gl_coord_t definition for detailed explanation.

Returns

Nothing.

Precondition

Before calling this function, be sure to initialize driver and font. Use gl_set_driver and gl_set_font for that purpose.

See also

gl_set_font gl_set_font_orientation gl_set_pen_color gl_set_font_background_color gl_set_font_background

Example

 
#include "gl.h"
#include "board.h"
#include "tft8.h"
#include "resource.h"
 
static gl_driver_t driver;
static tft8_cfg_t tft_cfg;
 
void main()
{
 uint8_t distance = 20;
 
 // initialize driver
 TFT8_MAP_PINOUTS_16BIT(tft_cfg);
 tft_cfg.board = &TFT_BOARD_7_CAPACITIVE; 
 tft8_init(&tft_cfg, &driver);
 
 // prepare display for drawing
 gl_set_driver(&driver); // set initialized driver
 gl_clear(GL_CHARLESTON_GREEN); // clear display
 
 // it's necesary to set the font
 gl_set_font(test_font);
 
 /*
 * HORIZONTAL CHAR
 * (x, y) coordinates determins top left of rect area that character is going to be drawn in
 */
 gl_set_font_orientation(GL_FONT_HORIZONTAL);
 gl_set_pen_color(GL_YELLOW);
 
 gl_draw_char('H', 0, 0); 
 gl_draw_char('e', 13, 9); 
 gl_draw_char('l', 25, 19); 
 gl_draw_char('l', 30, 24); 
 gl_draw_char('o', 35, 32); 
 
 /*
 * VERTICAL CHAR
 * (x, y) coordinates determins bottom left of rect area that character is going to be drawn in
 */
 gl_set_font_orientation(GL_FONT_VERTICAL);
 gl_set_pen_color(GL_GREEN);
 
 gl_draw_char('w', 46, 55); 
 gl_draw_char('o', 55, 42); 
 gl_draw_char('r', 60, 30); 
 gl_draw_char('l', 65, 23); 
 gl_draw_char('d', 68, 18); 
 gl_draw_char('!', 70, 5); 
 
 // characters out of display will not be drawn at all
 gl_draw_char('a', -50, 50); // left of display - invisible
 gl_draw_char('b', gl_get_screen_width() + 50, 50); // right of display - invisible
 gl_draw_char('c', 50, -50); // above the display - invisible
 gl_draw_char('d', 50, gl_get_screen_height() + 50); // under the display - invisible
 
 // characters on the border will be croped (by default border is set to display dimension)
 gl_set_pen_color(GL_RED);
 
 gl_draw_char('e', -10, 100); // on the left line of display - cut off
 gl_draw_char('F', gl_get_screen_width() - 10, 100); // on the right line of display - cut off
 gl_draw_char('G', 100, 5); // on the top line of display - cut off
 gl_draw_char('H', 100, gl_get_screen_height()+3); // on the bottom line of display - cut off
 
}
 

gl_draw_text()

void gl_draw_text	(	const char *__generic	text,
		gl_coord_t	x,
		gl_coord_t	y
	)

This function writes a text on a display with top left pixel situated at given x and y coordinates using current font and pen. To write a text with background use gl_set_font_background and gl_set_font_background_color. It is possible to choose text orientation using the gl_set_font_orientation. If a given text is written out of the display, the surplus will be cropped. Character that can be drawn is determined by the used font; if not supported by the font, it won't be printed and the behavior in that case is undefined. Character '\n' is not suported. If text is NULL nothing will be drawn.

Parameters

[in]	text	Text to draw.
[in]	x	X coordinate. See gl_coord_t definition for detailed explanation.
[in]	y	Y coordinate. See gl_coord_t definition for detailed explanation.

Returns

Nothing.

Precondition

Before calling this function, be sure to initialize driver and font. Use gl_set_driver and gl_set_font for that purpose.

See also

gl_set_font, gl_set_font_orientation, gl_set_pen_color, gl_set_font_background_color, gl_set_font_background.

Example

 
#include "gl.h"
#include "board.h"
#include "tft8.h"
#include "resource.h"
 
static gl_driver_t driver;
static tft8_cfg_t tft_cfg;
 
static const char lorem[] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.";
 
void main()
{
 // initialize driver
 TFT8_MAP_PINOUTS_16BIT(tft_cfg);
 tft_cfg.board = &TFT_BOARD_7_CAPACITIVE; 
 tft8_init(&tft_cfg, &driver);
 
 // prepare display for drawing
 gl_set_driver(&driver); // set initialized driver
 gl_clear(GL_CHARLESTON_GREEN); // clear display
 
 // before drawing text, font must be set
 gl_set_font(test_font);
 
 // horizontal and vertical text starts from same coordinates
 // does not overlaps
 gl_set_font_orientation(GL_FONT_HORIZONTAL);
 gl_set_pen_color(GL_GREEN);
 gl_draw_text("Horizontal text", 50, 200); // drawing goes from given point to left display side 
 
 gl_set_font_orientation(GL_FONT_VERTICAL);
 gl_set_pen_color(GL_YELLOW);
 gl_draw_text("Vertical text", 50, 200); // drawing goes from given point to top display side
 
 // vertical and vertical-column text starts from same coordinates
 // does not overlaps
 gl_set_font_orientation(GL_FONT_VERTICAL_COLUMN);
 gl_set_pen_color(GL_RED);
 gl_draw_text("Column", 300, 200); // drawing goes from given point to bottom display side 
 
 gl_set_font_orientation(GL_FONT_VERTICAL);
 gl_set_pen_color(GL_YELLOW);
 gl_draw_text("Vertical text", 300, 200); 
 
 // horizontal and vertical-column text starts from same coordinates
 // does overlaps
 gl_set_font_orientation(GL_FONT_HORIZONTAL);
 gl_set_pen_color(GL_GREEN);
 gl_draw_text("Horizontal text", 500, 200); 
 
 gl_set_font_orientation(GL_FONT_VERTICAL_COLUMN);
 gl_set_pen_color(GL_RED);
 gl_draw_text("Column", 500, 200); 
 
 // special characters
 gl_set_font_orientation(GL_FONT_HORIZONTAL);
 gl_set_pen_color(GL_GREEN);
 gl_draw_text("Make sure your font supports any special characters you're using!", 100, 20);
 
 gl_draw_text(NULL, 150, 160); // NULL pointers are ignored
 // gl_draw_text("\t", 150, 160); // if character out of font is drawn, undefined behavior will occur 
 // gl_draw_text("Newline \n is not supported", 150, 180); // new line is not supported
}
 

gl_get_text_dimensions()

gl_size_t gl_get_text_dimensions

(

const char *__generic

text

)

This function calculates text dimension. The size of the text depends on the font which has been set by gl_set_font.

Parameters

[in]

text

Text to measure.

Returns

Size of text if font is set, otherwise returns size = {0, 0}. See gl_size_t definition for detailed explanation.

Precondition

Before calling this function, be sure to initialize font by calling gl_set_font.

See also

gl_draw_text, gl_draw_char, gl_set_font.

Example

 
#include "gl.h"
#include "board.h"
#include "tft8.h"
#include "resource.h"
#include "conversions.h"
 
static gl_driver_t driver;
static tft8_cfg_t tft_cfg;
 
static const char* strings[] =
{
 "a", 
 "aa", 
 "ab", 
 "word",
 "two words",
};
 
void print_dimension(gl_size_t size, gl_coord_t x, gl_coord_t y)
{
 char buff[10];
 uint16_to_str(size.width, buff);
 gl_draw_text(buff, x, y);
 uint16_to_str(size.height, buff);
 gl_draw_text(buff, x + 30, y);
}
 
void main()
{
 int y = 10;
 gl_size_t dim;
 
 // initialize driver
 TFT8_MAP_PINOUTS_16BIT(tft_cfg);
 tft_cfg.board = &TFT_BOARD_7_CAPACITIVE; 
 tft8_init(&tft_cfg, &driver);
 
 // prepare display for drawing
 gl_set_driver(&driver); // set initialized driver
 gl_clear(GL_CHARLESTON_GREEN); // clear display
 
 gl_set_font(test_font);
 
 // strings
 for (int i = 0; i < 5; i++)
 {
 dim = gl_get_text_dimensions(strings[i]);
 gl_draw_text(strings[i], 10, y );
 print_dimension(dim, dim.width + 30, y);
 y += 30;
 }
 
 // NULL pointer for text argument returns 0,0
 dim = gl_get_text_dimensions(NULL);
 gl_draw_text("NULL ptr dimensions", 10, y);
 print_dimension(dim, 300, y);
 y += 30;
 
 // empty string for text argument returns 0,0
 dim = gl_get_text_dimensions("");
 gl_draw_text("Empty string dimensions", 10, y);
 print_dimension(dim, 300, y);
 return;
}